| 翻訳と辞書 |
video codec
A video codec is an electronic circuit or software that compresses or decompresses digital video, thus converting raw (uncompressed) digital video to a compressed format or vice-versa. In the context of video compression, "codec" is a concatenation of "encoder" and "decoder"; a device that can only compress is typically called an encoder, and one that can only decompress is known as a decoder.
The format of the compressed data usually conforms to a standard video compression specification. The compression is typically lossy, meaning that the compressed video lacks some of the information present in the original video. A consequence of this is that decompressed video has lower quality than the original, uncompressed video because there is insufficient information to accurately reconstruct the original video.
There are complex relationships between the video quality, the amount of data used to represent the video (determined by the bit rate), the complexity of the encoding and decoding algorithms, sensitivity to data losses and errors, ease of editing, random access, and end-to-end delay (latency).
==History==
Historically, video was stored as an analog signal on magnetic tape. Around the time when the compact disc entered the market as a digital-format replacement for analog audio, it became feasible to also store and convey video in digital form. Because of the large amount of storage and bandwidth needed to record and convey raw video, a method was needed to reduce the amount of data used to represent the raw video. Since then, engineers and mathematicians have developed a number of solutions for achieving this goal that involve compressing the digital video data.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「video codec」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|